/**
 * Created by hjy on 2017/8/26.
 *
 * 爬虫
 */
var http = require('http')
var cheerio = require('cheerio')//需要安装 npm install cheerio
var url = 'http://www.imooc.com/learn/348'

function filterChapter(html) {
    var $ = cheerio.load(html)
    // 拿到每一大张的class
    var chapters = $('.chapter')//icon-chapter

    var courseData = []
    chapters.each(function (item) {
        var chapter = $(this)
        var chapterTitle = chapter.find('strong').text()
        var videos = chapter.find('.video').children('li')
        var chapterData = {
            chapterTitle: chapterTitle,
            videos: []
        }

        videos.each(function (item) {
            var video = $(this).find('.J-media-item')
            var videoTitle = video.text()
            var id = video.attr('href').split('video/')[1]

            chapterData.videos.push({
                title:videoTitle,
                id:id
            })
        })

        courseData.push(chapterData)
    })

    return courseData
}

function printCourseInfo(courseData) {
    courseData.forEach(function (item) {
        var chapterTitle = item.chapterTitle

        console.log(chapterTitle + '\n')

        item.videos.forEach(function (video) {
            console.log(' [' + video.id + ']' + video.title + '\n')
        })
    })
}

http.get(url,function (res) {
    var html = ''

    res.on('data',function (data) {
        html += data
    })

    res.on('end',function () {
        // console.log(html)

        var courseData = filterChapter(html)

        printCourseInfo(courseData);
    })
}).on('error',function () {
    console.log('获取课程数据出错')
})